Capacitors are one type of component which is commonly used in the fabrication of integrated circuit, for example in DRAM circuitry. A typical capacitor is comprised of two conductive electrodes separated by a non-conducting dielectric region. As integrated circuitry density has increased, there is a continuing challenge to maintain sufficiently high storage capacitance despite typical decreasing capacitor area. The increase in density of integrated circuitry has typically resulted in greater reduction in the horizontal dimension of capacitors as compared to the vertical dimension. In some cases, the vertical dimension of capacitors has increased.
One manner of forming capacitors is to initially form an insulative material within which an initial of one of the capacitor electrodes is formed. For example, an array of capacitor electrode openings (also referred to as storage node openings) for individual capacitors is typically fabricated in such insulative capacitor electrode-forming material. One typical capacitor electrode-forming material is silicon dioxide doped with one or both of phosphorus and boron. One common capacitor electrode construction is a so-called container capacitor or device. Here, a container or cup-like shaped capacitor electrode is formed within the opening. A capacitor dielectric material and another capacitor electrode are formed thereover within the container. Where it is desired to utilize the outer lateral surfaces of the container or other electrode shape, the capacitor electrode-forming material is typically etched back after forming the initial electrode to expose outer lateral side surfaces thereof and prior to forming the capacitor dielectric material.
The etch which is used to form the capacitor electrode openings can unfortunately be non-uniform across a wafer being fabricated. For example, typically at the edge of the wafer, it is recognized that some of this area will not be usable for fabricating integrated circuitry. Further in this area, the etch which is conducted to form the container openings typically does not extend nearly as deep into the substrate as occurs in other areas where usable circuitry die are fabricated, for example in area displaced from the wafer edge. Such results in the capacitor electrode structures formed in this edge area as not being as deep into the capacitor electrode-forming material as elsewhere over the wafer. Unfortunately, the etch back of the capacitor electrode-forming material to expose the outer lateral sides of the capacitor electrodes is typically wet and can exceed the depth of the these peripherally formed electrodes. Thereby, such electrodes are no longer retained on the wafer in their original positions, and accordingly lift off the wafer and redeposit elsewhere, leading to fatal defects.
While the invention was motivated in addressing the above identified issues, it is in no way so limited. The invention is only limited by the accompanying claims as literally worded, without interpretative or other limiting reference to the specification, and in accordance with the doctrine of equivalents.